Terry DelValle For the Times-Union Knock Out roses, introduced in 2000, are low-maintenance roses, but not no-maintenance flowers.

I added Knock Out roses to our yard a while back because I thought they didn’t need care. Mine are getting yellow and the leaves are dropping off just like they did last year. They have just never thrived. What am I doing wrong?

Perhaps you’re confusing “low maintenance” with “no maintenance.” Remember that the Knock Out roses may be tough, but they are still living, growing shrub roses and not artificial plants. Though they certainly require less work than a hybrid tea or a show rose, they still need the basics: good location; fertilization; watering, and the occasional pruning.

The breeder of The Knock Out roses, William Radler, said, “one of the goals in my life was to breed the maintenance out of roses.” Today, more than 80 million Knock Out roses have been sold since they were introduced in 2000, making them the most widely sold roses in the country. Clearly, they speak to the lazy gardener in all of us.

In Florida, these naturally compact shrubs’ showy flowers bloom practically year-round in most of the state. They are drought tolerant, self-cleaning, and resistant to black spot and powdery mildew.

But even with all these attributes, the Knock Out is still NOT a “no maintenance” plant and is susceptible to all the problems of other roses, albeit to a lesser degree.

Though they are “resistant” to black spot and powdery mildew, these fungi can still be a problem. Proper placement of your plant in the beginning is going to be the best preventive. Avoid planting them in locations where high humidity, poorly drained soil, poor air circulation, indirect sunlight or less than four to six hours of sunlight a day are common. If you do develop a fungal problem, occasional fungicide applications will help.

When you are inspecting your roses for problems, remember to look for common garden pests. Knock Out roses may be hardier and less susceptible to pest problems than most roses, but they can still become lunch for a passing pest invasion — aphids, spider mites, leafhoppers, thrips and on and on. Carefully identify the intruder and be sure it’s not one of the many beneficial insects that are natural predators to damaging pests. Expect insecticidal soap to be helpful.

Fertilize your Knock Outs. Just because they will continue to bloom without it, they’ll produce more and bigger blossoms with regular feeding throughout the growing season. Follow the instructions on the container of a product specially blended for roses. Check the label for application timing as well. You will find that they vary from product to product.

Finally, prune. All flowering shrubs are revitalized by proper pruning. In late winter or early spring, before the buds begin to appear, cut your shrub back and remove all dead and damaged branches. Some websites will recommend pruning to 12 inches above the soil, while others will recommend taking out no more than half the height and width. Remember that your goal is to improve the appearance and the health of the plant. You don’t want it putting all of its energy into growing leaves rather than flowers.

With just the minimum of attention, your Knock Outs should start performing.

My neighbor told me that I should start using coffee grounds in my yard. But won’t that much acid damage my plants?

Coffee grounds are a low-level source of nitrogen and a minor source of calcium and magnesium, making them a fine fertilizer. Even though grounds are reported to be somewhat acidic in some lab results, others indicate they are no more so than peat moss (peat moss is fairly acidic, 4.5 pH).

To be safe, use coffee grounds as a fertilizer for acid-loving plants such as azaleas, gardenias, camellias, hollies and dogwood trees.

Add coffee grounds to your compost bin. Coffee grounds are considered a “green” material, just like green, leafy waste you already compost and must always be mixed with dry brown material. If you’re counting on worms making your compost (known as vermicomposting), coffee grounds are an excellent food source for them.

My favorite use for coffee grounds was found in an article from the Hillsborough County extension office. The writer suggests using coffee grounds to repel slugs. Create a barricade around your plants with the abrasive grounds. Be careful, however, to not overdo it: Not only would a thick layer of grounds become moldy, but it could also become compacted and hinder water and air movement. As in so many cases, too much of a good thing is not always best.

All in all, you might want to thank your neighbor for the tip.

The persimmons are dropping off my tree. What can I do to save what’s left?

Several weeks after they bloom, persimmon trees may drop some of their fruit. No need to worry, and nothing to do about it. It’s natural for persimmons to drop some of their fruit and self-regulate the size of its crop. Be careful of over-fertilizing as this can increase fruit drop.

Paula Weatherby is a master gardener with the Duval County Extension Service and the University of Florida/IFAS.